Numerous attempts have been made to formulate laundry detergent compositions which provide the good cleaning performance expected of them and which also have good textile softening and anti-static properties. Attempts have been made to incorporate cationic textile softeners in anionic surfactant-based built detergent compositions employing various means of overcoming the natural antagonism between the anionic and cationic surfactants. For instance, U.S. Pat. No. 3,936,537, Baskerville et al., issued Feb. 3, 1976, discloses detergent compositions comprising organic surfactant, builders, and, in particulate form (10 to 500 microns), a quaternary ammonium softener combined with a poorly water-soluble dispersion inhibitor which inhibits premature dispersion of the cationic in the wash liquor. Even in these compositions some compromise between cleaning and softening effectiveness has to be accepted. Another approach to provide detergent compositions with softening ability has been to employ nonionic surfactants (instead of anionic surfactants) with cationic softeners. Compositions of this type have been described in, for example, German Pat. No. 1,220,956, assigned to Henkel, issued Apr. 4, 1964; and in U.S. Pat. No. 3,607,763, Salmen et al., issued Sept. 21, 1971. However, the detergency benefits of nonionic surfactants are inferior to those of anionic surfactants.
Other laundry detergent compositions have employed tertiary amines along with anionic surfactants to act as textile softeners. British Pat. No. 1,514,276, Kengon, published Jun. 14, 1978, employs certain tertiary amines with two long chain alkyl or alkenyl groups and one short chain alkyl group. These amines are useful as fabric softeners in detergent compositions when their isoelectric point is such that they are present as a dispersion of negtively charged droplets in the normally alkaline wash liquor, and in a more cationic form at the lower pH of a rinse liquor, and so become substantive to fabrics. The use of such amines, among others, in detergent compositions has also been previously disclosed in British Pat. No. 1,286,054, assigned to Colgate-Palmolive, published Aug. 16, 1972. British Pat. No. 1,514,276, assigned to Unilever, published Jun. 14, 1978, and in U.S. Pat. No. 4,375,416, Crisp et al., issued Mar. 1, 1983.
Another approach to provide anionic detergent compositions with textile softening ability has been the use of smectite-type clays, as described in U.S. Pat. No. 4,062,647, Storm et al., issued Dec. 13, 1977. These compositions, although they clean well, require large contents of clay for effective softening. The use of clay together with a water-insoluble cationic compound in an electrically conductive metal salt as a softening composition adapted for use with anionic, nonionic, zwitterionic and amphoteric surfactants has been described in British Pat. No. 1,483,627, assigned to Procter & Gamble, published Aug. 24, 1977.
British patent application Nos. 1,077,103 and 1,077,104, assigned to Bayer, published Jul. 26, 1967, disclose amine-anionic surfactant ion-pair complexes useful as antistatic agents. These complexes are applied directly to the fabric from an aqueous carrier. There is no suggestion in either of these references that such complexes could be added to detergent compositions to inpart fabric care benefits through-the-wash. In fact, such complexes are delivered in solubilized form and therefore could not be delivered through-the-wash.
Fatty acid-amine ion-pair complexes in granular detergents are disclosed in European patent application No. 133,804, Burckett-St.Laurent et al., published Jun. 3, 1985. While this complex delivers fabric conditioning benefits, the alkyl amine-anionic surfactant ion-pair complexes of the present invention provide superior antistatic performance.
It is therefore an object of the present invention to provide a conditioning agent which can be used through-the-wash (i.e., can be added to the wash prior to initiation of the rinse cycle) and provide excellent fabric conditioning benefits without significantly impairing the cleaning performance of detergent or other cleaning compositions. It is also an object of this invention to provide fabric care compositions, in both liquid and granular forms, which can be used through-the-wash and provide excellent fabric conditioning benefits without significantly impairing the cleaning performance of detergent or other cleaning compositions, that is also added prior to the rinse cycle. (As used above, the term "fabric care composition" refers to compositions containing at least one conditioning agent useful for fabric care, but not containing a significant amount of fabric cleaning ingredients.)
It is another object of this invention to provide a liquid detergent composition having a conditioning agent which provides excellent through-the-wash fabric conditioning without significantly impairing cleaning performance. (The term "detergent composition", as used above refers to compositions containing at least one conditioning agent useful for fabric care and also containing one or more fabric cleaning ingredients.)
It is yet another object of this invention to provide granular detergent compositions having a fabric conditioner which provides excellent through-the-wash fabric conditioning without significantly impairing cleaning performance.